On the release date of their new album, “What a Terrible World, What a Beautiful World,” the Portland band will be honored by Mayor Charlie Hales at City Hall, with a free event at 2 p.m. that will also feature a Decemberists performance.

As well, 50 Portland artists and small businesses have teamed up to create an art piece inspired by the Decemberists’ new album that will be presented at the event.

The Portland-based act has called the city home since its inception. Last January, singer Colin Meloy — headlining the Crystal Ballroom for the venue’s 100th birthday — told the story of how the band funded its debut “5 Songs” EP with the gig fee from another McMenamins performance. The band’s big Portland show in 2002? A performance at Lola’s Room that sold 75 tickets.

You might say they’ve come a long way: in March, they’ll headline the nearly-3,000-capacity Keller Auditorium, a show that’s already sold out. Their last album, 2011’s “The King is Dead,” topped the Billboard 200 chart.

The musical honor is a rare one for the city. In 2013, historic rock single “Louie Louie,” recorded by both the Kingsmen and Paul Revere and the Raiders in Portland in 1963, received its own “Louie Louie Day.”